Posted
by
CmdrTaco
on Tuesday October 12, 2010 @04:50PM
from the because-they-can dept.

FleaPlus writes "The BBC reports that the space agencies of Europe, Russia, and the US are in (very) preliminary discussions about a potential collaborative mission where astronauts would assemble a small spacecraft at the ISS, then fly it around the Moon and back. This is somewhat similar to previously-proposed commercial missions, with many elements adapted from spacecraft systems already in existence. This would also be a testbed for eventual asteroid and Mars missions, which would likely require modules to be launched on multiple rockets and assembled in space."

the money would be better spent offering a prize to the first company or organization that can send a ship around the moon and back....

offer $100 million to the first to do it...$50 million to the second....or make it $500 million to the first.......it will still be insanely cheaper than the governments funding it themselves...and the tech might actually get commercialized.

Apollo 11 was run from this perspective. Multiple launches (Apollo + Agena) docked in orbit to become the composite lunar spacecraft.

This is incorrect. Each manned Apollo mission used a single Saturn V. (Except for the Apollo 7 test flight, which used a Saturn IB.) Orbital docking occurred between the command/service module and lunar module launched on the same rocket.

Agena boosters were modified to practice docking during the Gemini program, but had no direct involvement in Apollo.

Not if you have to change inclination like anything coming from the ISS would have to do.

It depends. For example, I believe if you want to go into a lunar polar orbit, departing from the ISS's 51.6 degree inclination actually requires less propellant than if you were to depart from an equatorial orbit. If you want to go somewhere else that the ISS inclination is suboptimal for, all that means is that you need to carry up a little more propellant.

The ISS is in a 51 deg orbit (so the Russians can reach it from Kazakhstan), which is one the worst possible places to depart for the Moon from. Optimally, you want a transfer orbit coplanar with the Moon's orbit, which varies from 18-28 deg (depending of the time of year). This is because trajectory errors in coplanar orbits tend to cancel out, increasing safety, as well as reducing the mass of fuel required launch to the transfer orbit. So, either the ISS-launched mission does a very-expensive plane-change maneuver, or weighs more and is more unsafe than a conventionally launched mission. Either way, launching to the Moon (or any Lagrange Points) from the ISS is orbitally dumb.

BTW, the latitude of Kennedy Space Center is 28 deg, the furthest north it can be to optimally launch a mission to the Moon...

It's in the wrong orbit to do anything other than be reachable by launches from mainland Russia. It's not like no one ever thought of using the space station as a jumping-off point before, it's just that such ideas were made more or less impractical as soon as we decided to put the space station in this silly orbit.

Of course, the fact that the goal was to be reachable by launches from Baikonur means it's not a silly orbit, considering inclination changes are the most expensive in terms of delta-v (and money, as a result).